Transformable mesoporous organo-germano-silicas

• Novel bulky sol–gel silyl-germyl precursors were prepared from renewable fatty esters.
• Surface-reactive carboxylic silicates bearing hydrophobic fatty compounds were obtained.
• Thermal annealing affords dispersed mesoporous silica–germania mixed oxides.

The self-assembly and sol–gel polymerization of novel bimetallic alkoxysilyl-germyl-fatty acid methyl esters provide new class of organically functionalized mesoporous germano-silicas. These materials feature an SBA-15-type network and are structurally distinguished by the presence of hydrophobic buttress, reactive carboxylic groups and well-dispersed germanium within the inorganic framework. The accessibility of the carboxylic groups has been assessed by peptide coupling with amino-pyrene probe; the photo-electronic response of the latter being characteristic of well-separate dye embedded in a hydrophobic environment. Thermal treatment of these hybrid materials induces germanium migration to the silica walls given rise to purely inorganic mesoporous silica–germania mixed oxides (Si–O–Ge–O–Si).

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